Session IVB

The large kinetic barriers associated with redox
chemistry of relevance to energy storage can be circumvented by catalytic
pathways. Cofacial catalysts that are capable of small molecule activation
allow for preorganization of transition states and enable two or more metals to
participate, which decreases the demand on a single metal center. Metalloporphyrins can be assembled into a
cofacial conformations using molecular clips that enforce an offset between the
two macrocycles. Herein, we describe a system that assembles cobalt
5,10,15,20–tetra(4–pyridyl) porphyrins (Co–TPyP) with diruthenium clips to
furnish [Ru8(η6–p–PriC6H4Me)8(Co–TPyP)2(C6H2O4)4](O3SCF3)8 (Co prism).
Catalytic activity towards the reduction of oxygen is shown in both Co–TPyP and
the Co prism. This work encompasses the electrochemical oxygen reduction by
homogeneous solutions of Co–TPyP and Co prism.

T33

Quantifying
Analyte-Porous Silicon Interactions

Ari Darlow, Justin M. Reynard, Dustin T. McCall, and Frank V.
Bright

University at Buffalo, Department of Chemistry

Porous
silicon (pSi) has been studied for use in chemical sensing. Key to the success
of such a strategy is understanding and selectively controlling analyte-pSi
interactions. In this research I have been using the intrinsic pSi
photoluminescence (PL) to determine the analyte-dependent PL response from as
prepared, oxidized and silanized pSi. This presentation will describe our
measurement system and strategy and summarize the analyte-pSi thermodynamics we
have measured to date.

Next-generation
computer technologies will require ultrahigh-density data storage devices and
quantum computing based on isolated spin-carriers, so-called molecular
spintronics.1 Single-molecule magnets (SMMs) have shown great
potential for such applications.2 Their unique magnetic properties
enable SMMs to be used in spintronics for switching from total spin up to total
spin down on a molecular level, and therefore each molecule can be used as a
magnetic bit of information. Although a broad community works on the design of
new SMMs with improved properties,3 coupling of the nanoscale units
to the macroscopic world remains as a key challenge.4 Any practical
application of SMMs requires in the first step their organization in 2D or 3D
networks to allow read-and-write processes. Moreover, they are very delicate
molecules that break down easily and thus, they need to be protected to retain
their unique magnetic properties. Owed to their crystalline nature and
tunability, metal-organic frameworks (MOFs) provide an excellent means to
overcome this challenge. We investigated the unprecedented incorporation of
SMMs into multidimensional MOF matrixes, yielding new nanostructured composite
materials that combines key SMM properties with the functional properties of
MOFs. We believe that these findings might be crucial for the development of
spintronics in real world applications. In this presentation we will focus on
the fundamental understanding in the exciting structure-property relationships
of these SMM@MOF composite materials.

Achieving
directional charge transfer across semiconductor interfaces requires careful
consideration of relative band alignments. Simple binary semiconductors that
have been studied for photovoltaics have clearly defined valence and conduction
band edges and are difficult to reconfigure, thereby establishing limitations
on tunability of the thermodynamic driving force. One alternative is to
strategically position electronic states in a semiconductor through the
introduction of dopants or midgap states. In this seminar, a promising tunable
platform for light harvesting and excited-state charge transfer based on
interfacing β-Pb0.33V2O5 nanowires (having intrinsic midgap states) with CdSe
quantum dots will be presented. Two distinct routes are developed for
assembling the heterostructures: linker-assisted assembly mediated by a
bifunctional ligand and successive ionic layer adsorption and reaction (SILAR).
High-energy valence band X-ray photoelectron spectroscopy measurements indicate
that midgap states of the β-Pb0.33V2O5 nanowires are closely overlapped in
energy with the valence band edges of CdSe quantum dots. Transient absorption
measurements show that the midgap states in β-Pb0.33V2O5 can mediate
directional charge transfer of both electrons and holes from photoexcited CdSe
quantum dots (QDs) to the CB and midgap states of β-Pb0.33V2O5, respectively.

T36

Investigation
of PBDE-47 and its Hydroxylated Analog, 5-OH-BDE-47, in Humans: Metabolic or Environmental
Impact?

Austin Quinn and Joseph Gardella Jr.

University at Buffalo, Department of Chemistry

Soft
hydrophilic polymers are tailored to uptake and deliver growth factor proteins. Protein uptake is
measured by near edge X-ray emission fine structure NEXAFS spectra for HEMA
treated with varying protein treatment times. As well the soft X-ray microscope
at the Canadian light source can generate images in order to map the degree of
protein uptake in the image of a cross section.
The diffusion is also characterized using time of flight secondary ion
mass spectrometry TOF-SIMS. These two techniques have found continued use in
our lab, which provides characterization of specialized materials and chemical
mapping in. The work discussed in this presentation is a report of an ongoing
R&D collaboration between the Gardella lab, UB Medical School, and Roswell
Park Cancer Research Institute, collectively referred to as the tissue
engineering group. The group has focused on developing specialized polymeric
materials for medical applications and devices. This specific material differs
from our traditional HEMA membrane in that it has undergone a surface
optimization in order to prevent excessive transpiration of moisture from the
material.